/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    ArffSaver.java
 *    Copyright (C) 2004-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core.converters;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Vector;
import java.util.zip.GZIPOutputStream;

import weka.core.AbstractInstance;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.Utils;
import weka.core.WeightedInstancesHandler;

/**
 * Writes to a destination in arff text format.
 * <p/>
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -i &lt;the input file&gt;
 *  The input file
 * </pre>
 * 
 * <pre>
 * -o &lt;the output file&gt;
 *  The output file
 * </pre>
 * 
 * <pre>
 * -compress
 *  Compresses the data (uses '.arff.gz' as extension instead of '.arff')
 *  (default: off)
 * </pre>
 * 
 * <pre>
 * -decimal &lt;num&gt;
 *  The maximum number of digits to print after the decimal
 *  place for numeric values (default: 6)
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Stefan Mutter (mutter@cs.waikato.ac.nz)
 * @version $Revision$
 * @see Saver
 */
public class ArffSaver extends AbstractFileSaver implements BatchConverter, IncrementalConverter, WeightedInstancesHandler {

    /** for serialization */
    static final long serialVersionUID = 2223634248900042228L;

    /** whether to compress the output */
    protected boolean m_CompressOutput = false;

    /** Max number of decimal places for numeric values */
    protected int m_MaxDecimalPlaces = AbstractInstance.s_numericAfterDecimalPoint;

    /** Constructor */
    public ArffSaver() {

        resetOptions();
    }

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {
        Vector<Option> result = new Vector<Option>();

        result.addElement(new Option("\tCompresses the data (uses '" + ArffLoader.FILE_EXTENSION_COMPRESSED + "' as extension instead of '" + ArffLoader.FILE_EXTENSION + "')\n" + "\t(default: off)", "compress", 0, "-compress"));

        result.addElement(new Option("\tThe maximum number of digits to print after the decimal\n" + "\tplace for numeric values (default: 6)", "decimal", 1, "-decimal <num>"));

        result.addAll(Collections.list(super.listOptions()));

        return result.elements();
    }

    /**
     * returns the options of the current setup
     * 
     * @return the current options
     */
    @Override
    public String[] getOptions() {

        Vector<String> result = new Vector<String>();

        if (getCompressOutput()) {
            result.add("-compress");
        }

        result.add("-decimal");
        result.add("" + getMaxDecimalPlaces());

        Collections.addAll(result, super.getOptions());

        return result.toArray(new String[result.size()]);
    }

    /**
     * Parses the options for this object.
     * <p/>
     * 
     * <!-- options-start --> Valid options are:
     * <p/>
     * 
     * <pre>
     * -i &lt;the input file&gt;
     *  The input file
     * </pre>
     * 
     * <pre>
     * -o &lt;the output file&gt;
     *  The output file
     * </pre>
     * 
     * <pre>
     * -compress
     *  Compresses the data (uses '.arff.gz' as extension instead of '.arff')
     *  (default: off)
     * </pre>
     * 
     * <pre>
     * -decimal &lt;num&gt;
     *  The maximum number of digits to print after the decimal
     *  place for numeric values (default: 6)
     * </pre>
     * 
     * <!-- options-end -->
     * 
     * @param options the options to use
     * @throws Exception if setting of options fails
     */
    @Override
    public void setOptions(String[] options) throws Exception {

        setCompressOutput(Utils.getFlag("compress", options));

        String tmpStr = Utils.getOption("decimal", options);
        if (tmpStr.length() > 0) {
            setMaxDecimalPlaces(Integer.parseInt(tmpStr));
        }

        super.setOptions(options);

        Utils.checkForRemainingOptions(options);
    }

    /**
     * Set the maximum number of decimal places to print
     * 
     * @param maxDecimal the maximum number of decimal places to print
     */
    public void setMaxDecimalPlaces(int maxDecimal) {
        m_MaxDecimalPlaces = maxDecimal;
    }

    /**
     * Get the maximum number of decimal places to print
     * 
     * @return the maximum number of decimal places to print
     */
    public int getMaxDecimalPlaces() {
        return m_MaxDecimalPlaces;
    }

    /**
     * Returns the tip text for this property.
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String maxDecimalPlacesTipText() {
        return "The maximum number of digits to print after the decimal " + "point for numeric values";
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String compressOutputTipText() {
        return "Optional compression of the output data";
    }

    /**
     * Gets whether the output data is compressed.
     * 
     * @return true if the output data is compressed
     */
    public boolean getCompressOutput() {
        return m_CompressOutput;
    }

    /**
     * Sets whether to compress the output.
     * 
     * @param value if truee the output will be compressed
     */
    public void setCompressOutput(boolean value) {
        m_CompressOutput = value;
    }

    /**
     * Returns a string describing this Saver
     * 
     * @return a description of the Saver suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String globalInfo() {
        return "Writes to a destination that is in arff (attribute relation file format) " + "format. The data can be compressed with gzip in order to save space.";
    }

    /**
     * Returns a description of the file type.
     * 
     * @return a short file description
     */
    @Override
    public String getFileDescription() {
        return "Arff data files";
    }

    /**
     * Gets all the file extensions used for this type of file
     * 
     * @return the file extensions
     */
    @Override
    public String[] getFileExtensions() {
        return new String[] { ArffLoader.FILE_EXTENSION, ArffLoader.FILE_EXTENSION_COMPRESSED };
    }

    /**
     * Sets the destination file.
     * 
     * @param outputFile the destination file.
     * @throws IOException throws an IOException if file cannot be set
     */
    @Override
    public void setFile(File outputFile) throws IOException {
        if (outputFile.getAbsolutePath().endsWith(ArffLoader.FILE_EXTENSION_COMPRESSED)) {
            setCompressOutput(true);
        }

        super.setFile(outputFile);
    }

    /**
     * Sets the destination output stream.
     * 
     * @param output the output stream.
     * @throws IOException throws an IOException if destination cannot be set
     */
    @Override
    public void setDestination(OutputStream output) throws IOException {
        if (getCompressOutput()) {
            super.setDestination(new GZIPOutputStream(output));
        } else {
            super.setDestination(output);
        }
    }

    /**
     * Resets the Saver
     */
    @Override
    public void resetOptions() {

        super.resetOptions();
        setFileExtension(".arff");
    }

    /**
     * Returns the Capabilities of this saver.
     * 
     * @return the capabilities of this object
     * @see Capabilities
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();

        // attributes
        result.enableAllAttributes();
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enableAllClasses();
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Saves an instances incrementally. Structure has to be set by using the
     * setStructure() method or setInstances() method.
     * 
     * @param inst the instance to save
     * @throws IOException throws IOEXception if an instance cannot be saved
     *                     incrementally.
     */
    @Override
    public void writeIncremental(Instance inst) throws IOException {

        int writeMode = getWriteMode();
        Instances structure = getInstances();
        PrintWriter outW = null;

        if (getRetrieval() == BATCH || getRetrieval() == NONE) {
            throw new IOException("Batch and incremental saving cannot be mixed.");
        }
        if (getWriter() != null) {
            outW = new PrintWriter(getWriter());
        }

        if (writeMode == WAIT) {
            if (structure == null) {
                setWriteMode(CANCEL);
                if (inst != null) {
                    System.err.println("Structure(Header Information) has to be set in advance");
                }
            } else {
                setWriteMode(STRUCTURE_READY);
            }
            writeMode = getWriteMode();
        }
        if (writeMode == CANCEL) {
            if (outW != null) {
                outW.close();
            }
            cancel();
        }
        if (writeMode == STRUCTURE_READY) {
            setWriteMode(WRITE);
            // write header
            Instances header = new Instances(structure, 0);
            if (retrieveFile() == null && outW == null) {
                System.out.println(header.toString());
            } else {
                outW.print(header.toString());
                outW.print("\n");
                outW.flush();
            }
            writeMode = getWriteMode();
        }
        if (writeMode == WRITE) {
            if (structure == null) {
                throw new IOException("No instances information available.");
            }
            if (inst != null) {

                // write instance
                if (retrieveFile() == null && outW == null) {
                    System.out.println(inst.toStringMaxDecimalDigits(m_MaxDecimalPlaces));
                } else {
                    outW.println(inst.toStringMaxDecimalDigits(m_MaxDecimalPlaces));
                    m_incrementalCounter++;
                    // flush every 100 instances
                    if (m_incrementalCounter > 100) {
                        m_incrementalCounter = 0;
                        outW.flush();
                    }
                }
            } else {
                // close
                if (outW != null) {
                    outW.flush();
                    outW.close();
                }
                m_incrementalCounter = 0;
                resetStructure();
                outW = null;
                resetWriter();
            }
        }
    }

    /**
     * Writes a Batch of instances
     * 
     * @throws IOException throws IOException if saving in batch mode is not
     *                     possible
     */
    @Override
    public void writeBatch() throws IOException {
        if (getInstances() == null) {
            throw new IOException("No instances to save");
        }
        if (getRetrieval() == INCREMENTAL) {
            throw new IOException("Batch and incremental saving cannot be mixed.");
        }
        setRetrieval(BATCH);
        setWriteMode(WRITE);
        if (retrieveFile() == null && getWriter() == null) {
            Instances data = getInstances();
            System.out.println(new Instances(data, 0));
            for (int i = 0; i < data.numInstances(); i++) {
                System.out.println(data.instance(i).toStringMaxDecimalDigits(m_MaxDecimalPlaces));
            }
            setWriteMode(WAIT);
            return;
        }

        PrintWriter outW = new PrintWriter(getWriter());
        Instances data = getInstances();

        // header
        Instances header = new Instances(data, 0);
        outW.print(header.toString());

        // data
        for (int i = 0; i < data.numInstances(); i++) {
            if (i % 1000 == 0) {
                outW.flush();
            }
            outW.println(data.instance(i).toStringMaxDecimalDigits(m_MaxDecimalPlaces));
        }
        outW.flush();
        outW.close();

        setWriteMode(WAIT);
        outW = null;
        resetWriter();
        setWriteMode(CANCEL);
    }

    /**
     * Main method.
     * 
     * @param args should contain the options of a Saver.
     */
    public static void main(String[] args) {
        runFileSaver(new ArffSaver(), args);
    }
}
